Thebmostatic contbol of a vent in a chambeb



I H M. CONE May 1930' 'THERMOSTATIG CONTROL OF A VENT IN A crmmaan Original Filed April 19. 1926 3 sheets'sheet l g 4 I I a A u/lllllla VII H. M. com-z THERMOS'I'ATIC CONTROL OF A VENT IN A CHAMBER Original Filed April 19, 1926 2 Sheets-Sheet 171001 for.

l/awdrdflf (one lllflfrllrllllra 7 q Al Var/al/e wood.

'Reiatled May 27, 1930 UNITED s A res PATENT OFF-ICE HOWARD M. coins, or LoNeviEw, wasrimeron, AssreNoR or ONE-HALF ro cur-m LONG-BELL LUMBER COMIEANY, OF KANSAS CITY, .MISSOURI, A CORPORATION OF MISSOURI THERMOSTATIC CONTROL OF A VENT IN CHAMBER Original No. 1,705,176, dated March 12, 1929, Serial No. 103,048, filed April 19, 1926. Application for reissue filed March 22, 1930. Serial No. 438,847.

' use in a lumber kiln in this connection.

It is convenient to quote the following from BulletinA (October, 1925, edition) entitled .Tycos Instruments for Lumber Dry Kilns published by the Taylor Instrument Companics, of Rochester, New York.

It is well known that two of the most important factors in lumber drying are temperature and humidity. One of the advantages of kiln drying is, that it is possible to maintain proper drying conditions independent of Weather conditions, thereby controlling the drying process and the final moisture content. p

Even the most inefficiently operated kiln is capable of evaporating moisture from The real problem, however, is to remove the moisture in the shortest time possible, without impairing the quality of the stock [being dried, andwith the minimum of steam consumption and kiln supervision.

The amount of moisture in the air affects the rate at which the moisture is evaporated from the surface of the stock, and the extent to which thewood will dry.- If the air, is very dry (humidity too low) excessive evaporation causes the fibres to become stiff and (lry resuIting in extreme case hardening. This condition causes unequal stresses in the boards. which if allowed to continue, results in familiar defects, such as checking, warpingand in loss of time and expensive kiln operations. *n p Y To maintain proper drying conditions, by hand adjustment .of spray and heat line valves is practically impossible. Therefore, automatic devices for controlling the spray and heat 'line valves .were heretofore pro-' vidcd as described'in said bulletin.

But the mere automatic control of the.

causes inequalities in the temperatures in the kiln. Not only this, the latent heatgiven off by the condensation of the moisture in the lumber, after the spray line is turned off, tends to cause sudden rises in the temperature, and thus a sudden ,fall in relative humidity will result. A sudden increase in heat and corresponding fall in humidity will dry the lumber too quickly; and the last mentioned conditions cannot be anticipated nor prevent except by the opening of the covers of the vents in the roof of the 'kiln to permit the escape of the dead steam and heat.

At the present time the covers of the vents in the roof. of the kiln are manually operated by an attendant who may, or may not always, be on duty. In any event no matter how careful he is, he has no accurate means of knowing exactly how much, when orhow long to open or keep open these covers.

But regardless of the operators experi-' ence, and the skill which he ma acquire, it is not within human ability instantly to change the position of the roof covers, so that the proper temperature and humidity will always be maintained. The change in temperature and humidity has bccurred before the eye can detect it, or the hand prevent it.

The object of my invention is to provide an eflicient automatic control for the roof vents in dry kilns; thus to relieve the operator of the constant necessity of constant watching-and assuring that the roof vents will be controlled so as to cooperate with the" heatingl coils and the spray line to assure just the rig midity.-

I attain my object by providing automatic thermostatic controlled means for opening andclosing the spring line valve and the roof vents in timewith each other. This cont predetermined temperature and Ira-- trol, is efiected throu h the medium of a wet bulb or dry bulb simllar to the operation of said Tycos device, and located at any convenient'point within the kiln, and by providing means for imposing a variable interval of time between the operations of the spray line spray and heat lines is not suflicient. The valve and roof vent control,in that way assurdead steam and air which collects under the ing an accurate cooperation of all the means roof of the dry kiln and does not clrculate provided for placing the air with n the in 1 9 Q the desired state as to temperature and humidity, with regard to a run of a particular crating devices,

, Bothof these means are illustrated in the ac companying drawings, described. In the accompanying drawings, Fig.

and hereinafter fully "shows'a section ofthe roof of a kiln provided with a vent and means for controlling the outlet from the kiln through said vent, and illustrated. diagrammatically one combinationof devicesby which the vent controlling means are thermostatically operated in order to attain the above mentioned objects and results. The devices here shown for operating the vent controlling means are actuated by fluidpressure, and the thermostatic element provided for operating the vent-controlling means consists of devices at present employed for controlling the temperature and humidity of a kiln chamber.

Fig.' 2 shows a fragmentary perspective view of a section of the roof of a kiln provided with a number of vents, and the means for operating all these vents as a unit; L

to provide, on being lifted, at

Fig. 3 illustrates diflerent means, than that shown in Figs. 1 and 4 for-controlling the vent; the cover shown in Fig. 3 being adapted first only a small opening for the vent, and then a larger opening with the further lifting of the cover.

Fig. 4 shows an enlarged. view of the vent and cover thereof shown in Fig. 1 in order to illustrate more clearly the arrangement of the cover by which it is adjustable for varying the control of the vent outlet.

Fig. 5 illustrates diagrammatically that thethermostatically actuated means for con- 7 trolling the roof ventmay be varied; as for example, instead of using pressure actuating dry kiln has a vent c controlled-by a cover d;

means, electro-magnetically operating means ma be used; 4

pen the roof to of the kiln b are mounted,

V prises a cover 30 sure actuated device is suitably fastened. The lever is is fixed to rock-shaft, g, which is journaled on the roof of the kiln in bearings h as mentioned, and actuates the cover lever 7' from which i's'sus'pended the cover d. i

The cover as shown in Figs. 1 and 4 comrigidly suspended from the stem 6, which sets tightly over the vent c. A sleeve-31 is formed on theunderside of the cover 30 which fits loosely in the vent 0 providing a space 32 between the sleeve 31 and the side of the vent cto provide an opening on V i the cover, which is only slightly lifted. This Z sleeve 31 is provided with a number of triangular notches 33, so that as the cover is lifted the opening will gradually increase until the vent is opened to its fullest extent.

The arm is is weighted by a. movable-weight wt,the1 eby forcing the pressure actuated device -to operate against said weight, and in that way providing means for-regulating the amount of pressure required to lift the cover oil the vent for more or less opening the latter. It isassumed that the kiln is provided with a thermostatic control-of the Tycos type, the actuatingelement, thus the wet-bulb for example,

point in the kiln chamber.-

The Tycos' device, as well known, co1n, prises a ,Bourdon type of helical spring 1), actuated by the wet bulb thermometer m, and this spring 1 expands or contracts as the humidity in the kiln rises or falls. The

mitted by arm 9 to pen arm -r, recording all movements'on record'sheet t, whichis rotated by a clock (not shown) The pen arm is counter balanced by weight '1" and is pivotally supported at s. The movement of pen arm 7' is transmitted to pin-Valve-arm a: by a horizontal link n. Said pin-valve-armo is pivotally fixed ate and actuates pin 2 of the needle valve by means of the set screw 112 which holds the said'pin'2 in place against the fluid pressure in the valve chamber 3. V

": The direct set control, by whichthe desired humidity is set, is an ad us ting nut 2, connectedby arm 2 to the arm 3 which sets the pointer m for the desired thermostatic conditionsin the kiln chamber. On the arm y :being located at any convenient "toan desired degree.

in alinement a number of spaced vents a conis. a. slot y in which a stud 3 fixed on the trolled by dampers-or covers (2. These covers arm 'w'moves. To the stud y is fastened a hang fromrods e pivotally supported from coiled spring y by which the arm 0 carrying the ends of. arms '7, rigidly secured to a rockthe set screw ru is held against the pin 2. The" shaft g. This shaft is suitably journaled in arm w is pivotally fixed at'w, and may move bearmgs k mounted to the roof at. e freely the length of the slot 3 thus setting Prior to myinvention the rock-shaft was the distance the'pin arm v may move before rotated manually by means of an arm 9' set the pin 2 will be actuated. In the side of the at anydesired position by a, rack 9 as illusneedle valve 3 an air-leak is. providedas an escape for pressure in pipes 9 and 13, the airv leak being controlled by a set screw 4 as Re erring firstto Fig. 1: Theroof a of the usual. g v

As the humidity in the kiln 'ses above a The pressure actuated device raises the diapredetermined point the arm '1: nfluenced by phragm lever Ix; to which the stem of the pres the wet bulb thermometer m, opens the needle trate'd' by Fig. 2, thereby opening-the vents valve 3 and allows the pressure to flow from airreservoir 6 through supply pipe 5,v into chamber 4 of the needle valve. The pressure then flows through pipes 9 and 13 to the pressure actuated meansz' and 10, the latter controlling the spray line valve 11 as usual.

The weight wt, suspended from the arm is is provided, so as to impose greater resistance to the operation of the pressure actuated dem vice 2', in controlling the roof vent, than is imposed upon the pressure actuated device 10, by which the spray line valve 11 is oper- I ated; in that Way causing'the roof vent to be closed prior to the opening of the spray-line valve, and vice versa, causing the .closing'of the spray line valve before the opening of .the roof vent. The weight wt is adjustable in order'to vary the amount of resistance i1nposed on the pressure actuated device 2'. M

The device illustrated by Fig.1 operates as follows:

When the humidity rises in the kiln chamber, the Bourdon spring of the wet bulb thermometer will be actuated, moving the penarm, recording such change, and simultaneously opening the needle valve 2, and causing the pressure actuated device to be operatedto shut off the steam spray. Then if the humidity continues to rise, the pressure actuated device 2' controlling the roof vent will be operated; the timing of the vent opening after the closing of the spray IineLis accomplished by adjusting the weight wt. as mentioned. I

A too sudden opening of the vents must not be'permitted for such would cause the, fluctuation of the temperature and humidity. and produce case hardening and checking in the lumber. V

Inorder to prevent this it is necessary to gradually open the vents and it is preferable to arrange the vent opening and closing -means so as to operate these means at a predetermined accelerating rate. To thisend as-the wet bulb temperature rises, the cover is first lifted from off the vent thus permitting only a small amount of air to escape through the space 32 between the sleeve 31 and the vent a, which if not suflicient to relieve the excess wet bulb temperature so that the wet bulb thermometer will either cease rising or fall as the'case may be, the pressure'operating devices will continue to ift the cover arm until the V-shaped notches 33 are raised above the rim of'the vent '0,

thereby permitting a more rapid and accelerating rate of escape of the excess humidity until the wet bulb temperature falls and causes the cover arm to mo e downward and gradually closes the said v nt again. Likewise,'if after a short time the smaller opening of the vent should not be sufficient, the wet bulb temperature will continue to rise and will cause finally the larger cover plate to be (I lifted 011' the vent,

\ Referring to Fig. 3 showing another type of vent control which comprises'two parts (Z and d, the part (1 is fixed on the stem 6 by a set screw e and. covers a hole in the largercover d, which rests on the vent. The

larger cover dv moves freely on the stem e. On the lower end of said stem is a spider di,

which as the arm 7 rises, bears against and lifts the cover part (1. .Thus as the lever f rises the hole in the cover d is first opened, iving a partial-outlet for the vent b, and. finally the latter is opened to full extent. Set in the cover 01 are a number of adjusting screws d extending through and threaded into the spider (P, so that thetime the cover d will open before the cover 01 is opened, may be controlled. This construction is especially adapted to prevent the too rapid opening of v the cover and to permit the control devgice to maintain a constant wet bulb temperature, within the kiln as when the smaller cover (2 is first opened, and if the excess humidity is not sufficiently relieved, the pressure operating device will continue to lift the cover arm until the spider strikes-the larger cover plate d. When this occurs the weight of the larger cover plate will be imposed upon the cover arm f, and hence greater ressure will be reuired to lift the latter, w ich tends to resist t e greater opening of the-vent. The smalleropening of the vent may be sufiicient to relieve the excess wet bulb temperature; but if not the pressure will build up and finally will lift the cover arm further, thereby lifting the larger cover late off the vent and opening the latter wi e;

Referring now to Fig. ,5, the 'means here shown for operating the vent control are similar to those shown in Fig. 1, except for the 'subst tution of the electro-magnetie means as actuating power instead of fluid pressure.

The roof a, vent c, and covers d and d, are

the same as shown in Fig. 1. A solenoid scl'.

when energized raises the solenoid lever k to whichis aflixed the rock-shaft g, which 2.0-; tuates' the cover leverf,-from which is suspended the-.coiger controlling vent a.

The solenoid ad is actuated by the variable contact 20, which regulates the said solenoid so that'it'gradually raises the solenoid arm k, and thereby thecovers cl and d in succession as'before mentioned.

The plunger arm 21 controls the variable contact 20, andas the wet bulb theIn'lOInetI m actuates the plan er arm 21, according to the degree of humi ity-in'the kiln chamber,

the variable contact 20 controls the amount of current going to the'solenoid 8d. Asis ap parent when the solenoidis de-ener ized, the

vent covers will then be allowed to c ose down on saidvents. 4 i 1 The thermostatic control which I "provide for the roof vents of a kiln, as above described, may in like manner e applied to operate cold air gates located at the bottomj l of the kiln, or other means provided for inducing a circulation of the air within the kiln, these means to be operated in conjunction with, and relatively totheicontrol of saidroof vents. 1 V 7 With the above described'meanslfor efiect ing the thermostatic control of theroof vents the temperature and humidity conditions the kilnchamber may be accurately maind tained as desired. It also reduces the amount of; steam consumed in the spray, by automaticallyclosing the roof ventfland inducing the evaporation of'the'moisture from the a lumber, thereby utilizing; the evaporated V moisture as the medium for maintaining the desired humidity within thekiln.

While I have specifically mentioned they Tycos instrument in thefore oing description of my lnvention, it 1s, 0 course, to be I understood that any other thermostatically actuated instrument maybe used foroperating the vent controlling and therairj -condi tioning meansthat is the air humidi-fying means, orthe air heating means, or both 25.mea'nsof' "the kiln chamber. In other words, instead of the complementary air-con ditioning means above described, other, relatively, cooperating, variable, complementary air conditioning means may be employed, ac-

cording-to whether the particular condition of the air within the kilnvchamber to be effected is humidity, or temperature, or bothJ Likewise, while I have described my invention as particularly applicable to a kiln cham-.

' her for drying lumber, it may also be found 40 controlling said vent, pressure actuated practical for use in drying other articles.

Iclaim: 1 V 1. The combination with a chamber provided with a vent, of automatic means for means'for operating the" vent -control]ii1g.

means, a spray line withinfthe chamber, a

valve in said spray line, pressure actuated means for operating the spray line valve, an air line connected to each'of said pressureactuated means, a thermostatically controlled valve in said air line, the actuating element f of such thermostatic. control being located I so within said chamber, and means for difierenbyto cause theoperation of t e latter means i 1 relatively to'theoperation-of the spray line valve.

and on said vent, pressure actuated means for line within the chamber, a valve in said spray line, pressure actuated means for operating V the spray line valve, an, air line connected to each of'said pressure actuated means, a thermostaticallycon'trolled valve said air line,

tiating the pressure required for operating the spray line valve fromthatrequired for operating said vent controllin means', wherearm; a s s s with a chambe r pro vided Wlthfi; vent and a cover'for said vent, of automatic means for moving the cover oif operating the cover moving means, a spray.

the actuating element control being located within said chamber, an adjustable weight arrangedto impose more or less resistance to the lifting'of said vent cover, whereby to cause the opening of the of such thermostatic vent to follow the closing of the spray line and to close the vent'prior to the opening of the spray line.

' 3. In a kiln, and the like, in combination, a

vent in the kilnchamber, a control for the vent, means for conditioning vthe air within the kiln chamber, a control or said air-conditioningmeans, means operated by athermostaticinstrument located within the kiln chamber whereby said controls are operated,

and adjustable means for varying the time interval between the operating of the air conditioning means and the vent control.

4. In a kiln, and the like, in combination, a Y

vent in the kiln chamber, a control for the vent, a-spray line within the "kiln chamber, a

control for said spray line, means operated by a thermostati'c instrument located within .the kiln chamber, whereby saidcontrols are operated, adjustable means for varying the timeinterval between the operating of the spray line control and the vent control,

, Ina kiln, and the like, in combination, a vent in the kiln chamber,,a cover for the vent and means for operating the same, means for conditioning the air within the kiln chamber, a'control for said air conditioning means, means operated by a thermostatic instrument located within the kiln chamber whereby said cover operating means and said control are operated, and adjustable means for varying. the time interval between the operating of the air conditioning means and the means for operating the vent cover.

6. Inja kiln and the like, in combination with a vent in the kiln chamber, a cover for the vent, means for operating said cover,. Vmeans for conditioning the air within the kiln chamber, a controlfor said air conditioning means, means operated'b a thermo-' static instrument located witlim the kiln chamber whereby said cover and control are operated, and adjustable means for varying the time interval between the ocrating of the air conditioning means and t e vent cover,

ing the vent opening at a, rate varying as compared with the corresponding movements of thecover. 1 .In' a kiln and the like, in combination with a vent in the kiln chamber, a cover for the vent, means for operating the same, means for conditioning the air within the kiln chamber,'a control for said air conditioning means, means operated by a thermostatic instrument located within thekiln chamber whereby said cover operating means and said control are o erated, and. adjustable means for varying .t e time interval between the operating of the air conditioning means and the means for said cover operating means opening or clos operating the vent cover, the cover operating means opening and closing the .vent opening at a materially increased rate as compared with the similar movements of the cover/ 8. In a kiln, and the like, in combination, complementary unit-means for conditioning the. air within the kiln chamber, a control for each of said unit-means, and means operate by a thermostatic instrument located within the kiln chamber whereby said controls are operated respectively, one of said controls being variable relatively to the desired time interval between the operations ofsaid unitmeans.

9. In a kiln, and the like, in combination, complementary unit-means for conditioning the air within the kiln chamber, pressure actuated controls for said unit-means respectively, apressure line connected to controls,

a thermostatically controlled valve in said pressure line, the. actuating element of said thermostatic control being located within the kiln chamber, said pressure actuated controls being variable, whereby to differentiate the pressures required for their operation, respectively, and cause the operation of one of said unit-means relatively to the other.

HOWARD M. CONE. 

